1. Field of the Invention
The present invention relates to a material compatible with blood for medical use, which is brought into contact with an organism or a vital component, and more particularly to a material compatible with blood which has satisfactory anti-blood-clotting and mechanical properties.
2. Description of the Prior Art
In recent years, polymer materials excellent in moldability, elasticity, flexibility, and the like have been widely used as materials for medical use. Particularly, polymer materials of this type have been expected to be used in greater amounts as disposable containers such as an injection case, a blood bag, and a heart catheter, as well as artificial organs such as an artificial kidney, an artificial lung, an auxiliary circulating unit, and as artificial blood vessels. When the materials are used for medical purposes, various kinds of reactions that may compromise the vitality and/or viability of an organism may occur. In the case of blood, for example, a compatibility with blood is required. Anti-coagulation polymer materials provided hitherto can be obtained by the following three methods: (1) bonding heparin or an analog thereof to the surface of the polymer material; (2) applying a negative charge to the surface of the polymer material; and (3) making the surface of the polymer material inactive. The material of the present invention is obtained by (1). Method (1) is divided into three categories: (A) blending the polymer material with heparin or an analog thereof; (B) ion-bonding heparin or an analog thereof to a cationic group in the polymer material; and (C) covalent bonding heparin or an analog thereof to the polymer material. However, in anti-blood-clotting polymer materials obtained in Methods (A) and (B), heparin or the analog is detached from the surface of the polymer material when used over a long period of time under physiological conditions, so that these materials are inappropriate as medical materials which are used by being fixed in vivo. In contrast, in materials compatible with blood obtained in Method (C), heparin or the analog thereof is covalently bonded to the polymer material, so that these materials have an advantage in that heparin or the analog are not likely to be detached from the material. However, according to the conventional covalent bond, conformational changes are given to D-glucosamine and D-glucuronic acid which is heparin components, so that the compatibility with blood are minimized.